This invention relates to a novel uterine cannula. Gynecological laparoscopy often requires uterine elevation and mobilization to selectively expose the pelvic organs and peritoneal spaces. Uterine elevation is particularly indicated in tubal sterilization and other procedures where electric cautery is used. Uterine elevation separates the uterus and adnexae from the sigmoid colon and loops of small bowel present in the pelvic cavity, and minimizes the chance of burns or other injury to these structures.
It is also possible to perform several gynecologic procedures including tubal sterilization through a small suprapubic incision, with the use of an inner uterine cannula to elevate the pelvic organs and render these organs more readily accessible to surgical manipulations. Discussion of such a procedure can be found in Saunders, W. G. and Munsick, R. A.: Nonpuerperal Female Sterilization. Obstet. Gynec. 40:443, 1972 and Uchida, H.: Uchida's Abdominal Sterilization Technique. Proceedings of the Third World Congress of Obstetrics and Gynecology. Congressprint, Vienna, 1961. Vol. 1 page 26. Advantages of this technique, as compared to conventional laparotomy, include reduced operative time with improved visualization and increased ease of manipulation, shorter hospital stay related to speedier recovery and a diminutive scar.
Several prior art instruments have been specifically designed to serve the function of uterine elevation and mobilization. These include a tenaculum attached to the cervix, a metal sound inserted into the uterus, a combination instrument of a tenaculum and sound, a large curette, a modified Fletcher after-loading tandem with Teflon guard, a vacuum uterine cannula, the Semm's vacuum cannula, the Kahn balloon cannula, and the Cohen-Eder self-retaining cannula. These instruments are generally useful, but share two distinct disadvantages.
First, the force of elevation is directed against the cervix and with the exception of the metal sound and curette only splinting of the uterine cavity is provided. The above applications are potentially safe, but do not provide adequate fundal elevation, particularly in patients with soft, retroverted uteri.
Second, uterine perforation can occur if force is inadvertently directed against the uterine corpus or fundus through the proximally protruding metal rod. Effective fundal elevation can be obtained with the use of a protruding metal rod, but the application is potentially more hazardous. Uterine perforations have been reported with the use of existing instruments.
Therefore, there is a need for a uterine cannula which is safe if a force is directed against the uterine corpus or fundus, is useful to permit uterine insufflation and injection, and also can be operated to effectively seal the cervix during insufflation and injection. It is, of course, desirable for such an instrument to be relatively inexpensive, simple to manufacture and simple to operate.
From the foregoing, it can be seen that an object of the present invention is to provide a uterine cannula which provides effective fundal elevation.
Another object of the present invention is to provide a uterine cannula which is safe and prevents uterine perforation from occurring.
A further object of the present invention is to provide a uterine cannula which has a soft end, which soft end will not pierce the uterine corpus or fundus but can be utilized for sealing the cervix.
A still further object of the present invention is to provide a uterine cannula which is simple in construction and easy to produce.
Another object of the present invention is to provide a uterine cannula which is easy to operate to provide both adequate and safe uterine fundal elevation and mobilization.
Other objects and advantages of the invention will become apparent as the description proceeds.